A variety of members are mounted on inner and outer sides of a container such as a fuel tank. A variety of technologies have been suggested as a method of mounting those members. A metallic fuel tank has been conventionally used. A resin fuel tank molded by resin such as thermoplastic resin is recently used from standpoints of weight reduction and the like. Considering this situation, a new technology has been suggested as a method of mounting a component to the fuel tank and the like.
Japanese Patent No. 5,871,280B discloses a method and a system for connecting a constitutional component to a molded product. The method disclosed in Japanese Patent No. 5,871,280B includes (a) a process of providing a constitutional component having a void in the vicinity of a wall of a molded product to be blow-molded and providing the void of the constitutional component in a recess part provided in a mold surface of a mold, (b) a process of overlapping a part of the constitutional component and a part of the wall of the molded product while the wall of the molded product is still at least partially melted, and (c) a process of cooling the wall of the molded product together with the part of the constitutional component overlapping the part of the wall of the molded product so as to maintain connection between the constitutional component and the wall of the molded product. In the process (b), at least one tool is moved in association with the constitutional component, so that the tool moves a part of the wall of the molded product with being engaged with the part of the wall of the molded product and the part of the wall of the molded product is thus at least partially moved to the void until the part of the wall of the molded product overlaps the part of the constitutional component.
Japanese Patent No. 5,871,280B discloses the method of mounting the constitutional component to the wall of the molded product to be blow-molded. In this method, during the blow molding, the parison and the constitutional component are contacted with the wall of the mold, for example, the recess part of the wall, the mold is closed and the air is then blown (blow up). At this time, a part of the parison is moved to the void of the constitutional component, so that a part of the wall of the parison is sandwiched between the two parts of the constitutional component, and the parison and the constitutional component are thus joined.
According to the method disclosed in Japanese Patent No. 5,871,280B, since the mold is closed in a state where a gap is formed between the constitutional component and the parison, the gas staying in the gap cannot escape. As a result, the movement of the parison to the void of the constitutional component is obstructed by a pressure of the staying gas, so that the joining strength of the constitutional component and the parison may be lowered.